Exciplex, organic electroluminescent element

Abstract

The application provides an exciplex and an organic electroluminescent element. The exciplex is composed of an electron donor type compound and an electron acceptor type compound, the electron donor type compound has a structure shown in general formula A or general formula B, and the electron acceptor type compound has a structure shown in general formula C. Compared with a host material used in a light-emitting layer of a conventional organic electroluminescent element, the host material, i.e. the exciplex, can increase the overlap between the emission spectrum of the host material and the absorption spectrum of a guest material, thereby increasing the efficiency of energy transfer. Meanwhile, the exciplex has a small singlet-triplet energy level difference ΔE ST , can improve the effective utilization rate of exciton energy, and further balances the transmission capacity of holes and electrons. Based on this, the application can more effectively improve the luminous efficiency of the organic electroluminescent element.

Description

Technical Field

[0001] This invention relates to the field of organic electroluminescence technology, and more specifically, to an excitocomplex and an organic electroluminescent element. Background Technology

[0002] Organic electroluminescent elements, due to their characteristics such as thinness, wide viewing angle, high contrast, low power consumption, high response speed, full-color screen, and flexibility, are currently used in smartphones, tablets, automobiles, and are expanding into large-size applications such as televisions.

[0003] Organic light-emitting diodes (OLEDs) typically consist of multiple layers, including a hole injection layer, a hole transport layer, an electron blocking layer, and an emitting layer. Holes and electrons are injected from the anode and cathode, respectively, and then enter the emitting layer through the transport layer to recombine and emit light. The efficiency of the device depends on the recombination probability of holes and electrons; therefore, controlling the balance of charge carriers at both ends is crucial. The main control methods include: improving the injection and transport of holes and electrons, thereby increasing the probability of hole-electron recombination; improving the blocking properties of holes and electrons, thereby confining the generated excitons within the emitting layer to achieve high luminous efficiency; or using electron donor and electron acceptor materials to form an excitocomplex as the host, which can simultaneously transport electrons and holes, balancing them, reducing exciton quenching, and thus improving luminous efficiency. However, in existing technologies using electron donor and electron acceptor materials to form an excitocomplex, the balance between electrons and holes is poor during electron and hole transport, resulting in more exciton quenching and thus lower luminous efficiency of the OLED. Therefore, it is necessary to improve the electroluminescent elements to achieve a better balance between holes and electrons and higher luminous efficiency. Summary of the Invention

[0004] The main objective of this invention is to provide an exciton complex and an organic electroluminescent element to solve the problem in the prior art where the exciton complex is formed using electron donor and electron acceptor materials, resulting in a poor balance between electrons and holes during electron and hole transport and excessive exciton quenching, thus leading to a low luminous efficiency of the electroluminescent element.

[0005] To achieve the above objectives, according to one aspect of the present invention, an excimer complex is provided, comprising an electron donor compound and an electron acceptor compound, wherein the electron donor compound has a structure shown in general formula A or general formula B, and the electron acceptor compound has a structure shown in general formula C.

[0006]

[0007] Among them, L1 and L2 are each independently selected from C6 to C6. 18The aryl groups; Ar1, Ar2, Ar3, Ar4, Ar5, and Ar6 are each independently selected from substituted or unsubstituted C6–C6 groups. 18 aryl or heteroaryl.

[0008] Furthermore, L1 and L2 are each independently selected from phenylene, biphenylene, or fluorene; Ar1, Ar2, Ar3, Ar4, Ar5, and Ar6 are each independently selected from phenyl, biphenyl, naphthyl, phenanthryl, fluorene, carbazole, or dibenzofuranyl.

[0009] Furthermore, the electron-donating compounds of general formula A are compounds having formulas A1 to A33, wherein formulas A1 to A33 are:

[0010]

[0011]

[0012]

[0013] Furthermore, the electron-donating compounds of general formula B are compounds having formulas B1 to B30, wherein formulas B1 to B30 are:

[0014]

[0015]

[0016]

[0017]

[0018] Furthermore, the electron-donating compounds of general formula C are compounds having formulas C1 to C39, wherein formulas C1 to C39 are:

[0019]

[0020]

[0021]

[0022]

[0023] To achieve the above objectives, according to one aspect of the present invention, an organic electroluminescent element is provided, comprising an anode layer, a hole injection layer, a first hole transport layer, a second hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a cathode layer stacked sequentially; wherein the light-emitting layer comprises a host material and a guest material, and the host material is the excimer complex described above.

[0024] Furthermore, the guest material is any one or more phosphorescent green dyes represented by general formula I:

[0025]

[0026] Among them, R1, R2, R3, R4, R5, R6, and R7 are each independently selected from hydrogen, deuterium, halogen atoms, and substituted or unsubstituted C1 to C2 atoms. 10 Alkyl, substituted or unsubstituted C6-C 30 aryl, or substituted or unsubstituted C5-C 30 Mixed aromatic compounds.

[0027] Furthermore, phosphorescent green dye is

[0028] Furthermore, by weight percentage, the content of the host material in the luminescent layer is 92–98 wt%, and the content of the guest material is 2–8 wt%.

[0029] This invention utilizes the combination of compounds with specific general formulas A or B and general formula C to form excitocomplexes, resulting in a wider full width at half maximum (FWHM) emission spectrum. Consequently, compared to the host material used in the emitting layer of conventional organic electroluminescent devices, the host material of this invention (i.e., the excitocomplex described above) can increase the overlap between the emission spectrum of the host material and the absorption spectrum of the guest material, thereby increasing the energy transfer efficiency. Simultaneously, the excitocomplex of this invention exhibits a smaller singlet-triplet energy level difference ΔE. ST Its triplet excitons can be converted into singlet excitons through a reverse intersystem crossing process, which will promote long-range inter-material communication between host and guest materials. The energy transfer process suppresses Dexter energy transfer to avoid energy loss, thereby effectively utilizing exciton energy and further balancing the transport capabilities of holes and electrons. Based on this, the present invention can more effectively improve the luminous efficiency of organic electroluminescent devices. Attached Figure Description

[0030] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0031] Figure 1 A schematic diagram of the structure of an organic electroluminescent device according to a preferred embodiment of the present invention is shown.

[0032] The above figures include the following reference numerals:

[0033] 10. Anode layer; 20. Hole injection layer; 30. First hole transport layer; 40. Second hole transport layer; 50. Light-emitting layer; 60. Electron transport layer; 70. Electron injection layer; 80. Cathode layer. Detailed Implementation

[0034] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0035] As described in the background section, when existing technologies utilize electron donor and electron acceptor materials to form excitocomplexes to simultaneously transport electrons and holes, there is a poor balance between the two, resulting in more exciton quenching and thus a low luminescence rate of the electroluminescent element.

[0036] To address this problem, the present invention provides an excimer complex composed of an electron donor compound and an electron acceptor compound, wherein the electron donor compound has the structure shown in general formula A or general formula B, and the electron acceptor compound has the structure shown in general formula C.

[0037]

[0038] Among them, L1 and L2 are each independently selected from C6 to C6. 18 The aryl groups; Ar1, Ar2, Ar3, Ar4, Ar5, and Ar6 are each independently selected from substituted or unsubstituted C6–C6 groups. 18 aryl or heteroaryl.

[0039] This invention utilizes the combination of compounds with specific general formulas A or B and general formula C to form excitocomplexes, resulting in a wider full width at half maximum (FWHM) emission spectrum. Consequently, compared to the host material used in the emitting layer of conventional organic electroluminescent devices, the host material of this invention (i.e., the excitocomplex described above) can increase the overlap between the emission spectrum of the host material and the absorption spectrum of the guest material, thereby increasing the energy transfer efficiency. Simultaneously, the excitocomplex of this invention exhibits a smaller singlet-triplet energy level difference ΔE. ST Its triplet excitons can be converted into singlet excitons through a reverse intersystem crossing process, which will promote long-range inter-material communication between host and guest materials. The energy transfer process suppresses Dexter energy transfer to avoid energy loss, thereby effectively utilizing exciton energy and further balancing the transport capabilities of holes and electrons. Based on this, the present invention can more effectively improve the luminous efficiency of organic electroluminescent devices.

[0040] Preferably, L1 and L2 are each independently selected from phenylene, biphenylene, or fluorene; Ar1, Ar2, Ar3, Ar4, Ar5, and Ar6 are each independently selected from phenyl, biphenyl, naphthyl, phenanthryl, fluorene, carbazole, or dibenzofuranyl. Based on this, the excimer complex of the present invention has a wider full width at half maximum (FWHM) emission spectrum and a singlet-triplet energy level difference ΔE. ST Smaller size results in higher exciton energy utilization and a better balance between hole and electron transport capabilities. Consequently, organic light-emitting devices composed of the above exciton complex exhibit better luminous efficiency.

[0041] To further balance the transport capabilities of holes and electrons, the electron-donating compounds of general formula A are compounds having formulas A1 to A33, wherein formulas A1 to A33 are:

[0042]

[0043]

[0044]

[0045] To further balance the transport capabilities of holes and electrons, the electron-donating compounds of general formula B are compounds having formulas B1 to B30, wherein formulas B1 to B30 are:

[0046]

[0047]

[0048]

[0049]

[0050] To further enhance the synergistic effect of electron donor and electron acceptor materials, thereby further balancing the transport capabilities of holes and electrons and improving the luminescence efficiency of electroluminescent elements, it is preferred that the electron donor compounds of general formula C be compounds having formulas C1 to C39, wherein formulas C1 to C39 are:

[0051]

[0052]

[0053]

[0054]

[0055] In a preferred embodiment, the preparation route of compound A is as follows:

[0056]

[0057] The preparation route of compound B is shown below:

[0058]

[0059] The preparation route of compound C is shown below:

[0060]

[0061] The present invention also provides an organic electroluminescent element, such as... Figure 1 As shown, it includes an anode layer 10, a hole injection layer 20, a first hole transport layer 30, a second hole transport layer 40, a light-emitting layer 50, an electron transport layer 60, an electron injection layer 70, and a cathode layer 80 stacked sequentially; wherein, the light-emitting layer 50 includes a host material and a guest material, and the host material is the excimer complex mentioned above.

[0062] Based on the reasons stated above, this invention combines the above-mentioned compound of general formula A or general formula B with compound of general formula C to form an excitocomplex, which further balances the transport capacity of holes and electrons, thereby reducing exciton quenching and thus significantly improving the luminous efficiency of organic electroluminescent elements.

[0063] Preferably, the guest material is any one or more phosphorescent green dyes represented by general formula I:

[0064]

[0065] Among them, R1, R2, R3, R4, R5, R6, and R7 are each independently selected from hydrogen, deuterium, halogen atoms, and substituted or unsubstituted C1 to C2 atoms. 10 Alkyl, substituted or unsubstituted C6-C 30 aryl, or substituted or unsubstituted C5-C 30 Heteroaryl groups. Based on this, the organic electroluminescent element of the present invention emits green light.

[0066] Preferably, the phosphorescent green dye is Based on this, the overlap between the emission spectrum of the host material and the absorption spectrum of the guest material in the organic electroluminescent element of the present invention can be further increased, thereby increasing the energy transfer efficiency and further improving the luminous efficiency of the element.

[0067] To further improve the luminous efficiency of the element, preferably, the content of the host material in the light-emitting layer 50 is 92-98 wt% and the content of the guest material is 2-8 wt% by weight.

[0068] In a preferred embodiment, refer to Figure 1The structure shown is used to fabricate an organic electroluminescent element using a SunicSP1710 vapor deposition machine. The specific steps are as follows: First, a glass substrate (Corning glass 40mm×40mm×0.7mm) coated with 135nm ITO (indium tin oxide) is ultrasonically washed with isopropanol and pure water for 5 minutes each, followed by ultraviolet ozone cleaning. Then, the glass substrate is transferred to a vacuum deposition chamber as the anode layer 10. HT1 and HD are co-doped (HD doping mass ratio is 4%) and deposited on a transparent ITO electrode under vacuum (approximately 10...). -7 A hole injection layer 20 is formed by thermal deposition of HT1 with a thickness of 20 nm. A 90 nm thick HT1 layer is then vacuum-deposited on top of the hole injection layer 20 to form a first hole transport layer 30. A 10 nm thick HT2 layer is then vacuum-deposited on top of the first hole transport layer 30 to form a second hole transport layer 40. A 30 nm thick light-emitting layer 50 is then vacuum-deposited on top of the second hole transport layer 40. The light-emitting layer 50 is composed of 3% by mass of phosphorescent green guest GD1, 48.5% by mass of compound A3, and 48.5% by mass of compound C1. Then, an electron transport layer 60 with a thickness of 30 nm is formed by vacuum deposition of ET1 doped with 50% LiQ (lithium 8-hydroxyquinoline). Finally, a 2 nm thick layer of ytterbium (Yb, as the electron injection layer 70) and a magnesium-silver alloy with a doping mass ratio of 10:1 are sequentially deposited to form a cathode layer 80. Finally, the component was transferred from the deposition chamber to the glove box and encapsulated with UV-curable epoxy resin and a glass cover containing a desiccant. During the above manufacturing steps, the deposition rates of the organic material, ytterbium, and Mg were maintained at 0.1 nm / s, 0.05 nm / s, and 0.2 nm / s, respectively. The component structure is represented as: ITO (135 nm) / HT1:4%HD (20 nm) / HT1 (90 nm) / HT2 (10 nm) / compound A3:compound C1:GD1 (48.5%:48.5%:3%) / ET1:LiQ (5:5, 30 nm) / Yb (2 nm) / Mg:Ag (10:1, 150 nm). The structures of HT1 (CAS#:1174006-39-3), HD (PubChem CID 124163074), HT2 (PubChem CID 121477644), GD1, and ET1 (PubChem CID 146557529) are as follows:

[0069]

[0070] In a preferred embodiment, refer to Figure 1The structure shown is used to fabricate an organic electroluminescent element using a SunicSP1710 vapor deposition machine. The specific steps are as follows: First, a glass substrate (Corning glass 40mm×40mm×0.7mm) coated with 135nm ITO (indium tin oxide) is ultrasonically washed with isopropanol and pure water for 5 minutes each, followed by ultraviolet ozone cleaning. Then, the glass substrate is transferred to a vacuum deposition chamber as the anode layer 10. HT1 and HD are co-doped (HD doping mass ratio is 4%) and deposited on a transparent ITO electrode under vacuum (approximately 10...). -7 A hole injection layer 20 is formed by thermal deposition of HT1 with a thickness of 20 nm. A 90 nm thick HT1 layer is then vacuum-deposited on top of the hole injection layer 20 to form a first hole transport layer 30. A 10 nm thick HT2 layer is then vacuum-deposited on top of the first hole transport layer 30 to form a second hole transport layer 40. A 30 nm thick light-emitting layer 50 is then vacuum-deposited on top of the second hole transport layer 40. The light-emitting layer 50 is composed of 3% by mass of phosphorescent green guest GD1, 48.5% by mass of compound Al2, and 48.5% by mass of compound C11. Then, an electron transport layer 60 with a thickness of 30 nm is formed by vacuum deposition of ET1 doped with 50% LiQ (lithium 8-hydroxyquinoline). Finally, a 2 nm thick layer of ytterbium (Yb, as the electron injection layer 70) and a magnesium-silver alloy with a doping mass ratio of 10:1 are sequentially deposited to form a cathode layer 80. Finally, the component was transferred from the deposition chamber to the glove box and encapsulated with UV-curable epoxy resin and a glass cover containing a desiccant. During the above manufacturing steps, the deposition rates of the organic material, ytterbium, and Mg were maintained at 0.1 nm / s, 0.05 nm / s, and 0.2 nm / s, respectively. The component structure is represented as: ITO (135 nm) / HT1:4%HD (20 nm) / HT1 (90 nm) / HT2 (10 nm) / compound A12:compound C11:GD1 (48.5%:48.5%:3%) / ET1:LiQ (5:5, 30 nm) / Yb (2 nm) / Mg:Ag (10:1, 150 nm).

[0071] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0072] Example 1

[0073] 1. Synthesis of compound A2:

[0074]

[0075] 13.9 g (50 mmol) of 4-(4-chlorophenyl)dibenzo[b,d]furan, 200 mL of N-([1,1'-biphenyl]-4-yl)-9,9-dimethyl-9H-fluorene-2-amine, 50 mmol of N-toluene, and 5.8 g (60 mmol) of sodium tert-butoxide were added to a 500 mL round-bottom flask. The mixture was stirred and heated to 50 °C under nitrogen protection. 0.46 g of catalyst Pd2dba3 (dibenzylacetone) and 2 g of tri-tert-butylphosphine (10 wt% toluene solution) were added. The mixture was then heated to reflux for 3 h before the reaction was stopped. The toluene was decolorized by passing it through a short silica gel column. The remaining toluene was then rotary evaporated to about 50 mL. After heating to 90 °C until completely dissolved, 200 mL of ethanol was added. The mixture was stirred and cooled to precipitate a solid. The solid was filtered and dried to give 21.7 g of white solid compound A2, with a yield of 72%. Compound A2 was further recrystallized twice using the same method, yielding a purity of 99.2%. Finally, after purification by sublimation, the purity reached 99.91%.

[0076] The structural characterization results of compound A2 are as follows:

[0077] 1H NMR (400MHz, CDCl3) δ8.08 (s, 1H), 8.00 (d, J = 20.0Hz, 2H), 7.88 (d, J = 20.0Hz, 2H), 7.75 (s, 2H), 7.60–7.45 (m, 9H), 7.45–7.19 (m, 11H), 1.69 (s, 6H).

[0078] 2. Synthesis of compound A3:

[0079]

[0080] 17.7 g (50 mmol) of 4-(4'-chloro-[1,1'-biphenyl]-3-yl)dibenzo[b,d]furan, 16.1 g (50 mmol) of bis(biphenyl)amine, 200 mL of toluene, and 5.8 g (60 mmol) of sodium tert-butoxide were added to a 500 mL round-bottom flask. The mixture was stirred and heated to 50 °C under nitrogen protection. 0.46 g of catalyst Pd2dba3 (dibenzylacetone) and 2 g of tri-tert-butylphosphine (10 wt% toluene solution) were added. The mixture was then heated to reflux for 3 h before the reaction was stopped. Toluene was decolorized using a short silica gel column, and then rotary evaporated to approximately 50 mL. The remaining toluene was heated to 90 °C until completely dissolved, and 200 mL of ethanol was added. The mixture was stirred and cooled to precipitate a solid, which was then filtered and dried to give 28.6 g of a white solid, compound A3, with a yield of 89%. Compound A3 was further recrystallized twice using the same method, yielding a purity of 99.1%. Finally, after purification by sublimation, the purity was 99.96%.

[0081] The structural characterization results of compound A3 are as follows:

[0082] 1 HNMR (400MHz, DMSO) δ8.22–8.07(m,3H),7.83(t,J=10.0Hz,1H),7.80–7.67(m,5H),7.66–7.55(m,9 H),7.55–7.45(m,2H),7.41(t,J=7.6Hz,5H),7.30(ddd,J=6.7,4.5,1.1Hz,2H),7.22–7.09(m,6H).

[0083] 3. Synthesis of compound A7:

[0084]

[0085] 17.7 g (50 mmol) of 4-(4'-chloro-[1,1'-biphenyl]-3-yl)dibenzo[b,d]furan, 12.97 g (50 mmol) of N-phenyldibenzo[b,d]furan-3-amine, 200 mL of toluene, and 5.8 g (60 mmol) of sodium tert-butoxide were added to a 500 mL round-bottom flask. The mixture was stirred and heated to 50 °C under nitrogen protection. 0.46 g of catalyst Pd2dba3 (dibenzylacetone) and 2 g of tri-tert-butylphosphine (10 wt% toluene solution) were added. The mixture was then heated to reflux for 3 h before the reaction was stopped. The toluene was decolorized by passing it through a short silica gel column. The remaining toluene was then rotary evaporated to about 50 mL. After heating to 90 °C until completely dissolved, 200 mL of ethanol was added. The mixture was stirred and cooled to precipitate a solid. The solid was filtered and dried to give 21.3 g of white solid compound A7, with a yield of 74%. Compound A7 was further recrystallized twice using the same method, yielding a purity of 99.0%. Finally, after purification by sublimation, the purity reached 99.68%.

[0086] The structural characterization results of compound A7 are as follows:

[0087] 1 H NMR (400MHz, CDCl3) δ8.13(s,1H),8.10–7.93(m,5H),7.70(s,1H),7.57(m,7H),7.39(m,5H),7.24m,5H),7.04(m,3H).

[0088] 4. Synthesis of compound A8:

[0089]

[0090] 4-(4'-chloro-[1,1'-biphenyl]-3-yl)dibenzo[b,d]furan (17.7 g, 50 mmol), N,9-bisphenyl-9H-carbazolyl-2-amine (16.7 g, 50 mmol), 200 mL of toluene, and sodium tert-butoxide (5.8 g, 60 mmol) were added to a 500 mL round-bottom flask. Under nitrogen protection, the mixture was stirred and heated to 50 °C. 0.46 g of catalyst Pd2dba3 (dibenzylacetone) and 2 g of tri-tert-butylphosphine (10 wt% toluene solution) were added. The mixture was then heated to reflux for 3 h before the reaction was stopped. Toluene was decolorized by passing it through a short silica gel column. The remaining toluene was then rotary evaporated to about 50 mL. After heating to 90 °C until completely dissolved, 200 mL of ethanol was added. The mixture was stirred and cooled to precipitate a solid. The solid was filtered and dried to give 22.5 g of white solid compound A8, with a yield of 68%. Compound A7 was further recrystallized twice using the same method, yielding a purity of 99.6%. Finally, after purification by sublimation, the purity reached 99.91%.

[0091] The structural characterization results of compound A8 are as follows:

[0092] 1 H NMR (400MHz, CDCl3) δ8.13(s,1H),8.10–7.93(m,5H),7.70(s,1H),7.57(m,7H),7.39(m,5H),7.24m,5H),7.04(m,3H).

[0093] 5. Synthesis of compound A12:

[0094]

[0095] 17.7 g (50 mmol) of 4-(4'-chloro-[1,1'-biphenyl]-3-yl)dibenzo[b,d]furan, 16.7 g (50 mmol) of bis(1-naphthyl)amine, 200 mL of toluene, and 5.8 g (60 mmol) of sodium tert-butoxide were added to a 500 mL round-bottom flask. The mixture was stirred and heated to 50 °C under nitrogen protection. 0.46 g of catalyst Pd2dba3 (dibenzylacetone) and 2 g of tri-tert-butylphosphine (10 wt% toluene solution) were added. The mixture was then heated to reflux for 3 h before the reaction was stopped. The toluene was decolorized using a short silica gel column, and then rotary evaporated to approximately 50 mL. The toluene was heated to 90 °C until completely dissolved, and 200 mL of ethanol was added. The mixture was stirred and cooled to precipitate a solid, which was then filtered and dried to give 23.8 g of a white solid, compound A12, with a yield of 81%. Compound A12 was further recrystallized twice using the same method, yielding a purity of 99.1%. Finally, after purification by sublimation, the purity was 99.85%.

[0096] The structural characterization results of compound A12 are as follows:

[0097] 1 H NMR (400MHz, CDCl3) δ8.22 (d, J = 16 Hz, 2H), 8.13–7.93 (m, 4H), 7.84 (td, J = 14, 8 Hz, 2H), 7.75–7.27 (m, 21H).

[0098] 6. Synthesis of compound B4:

[0099]

[0100] 9-[1,1'-biphenyl-4-yl]-3-bromo-9H-carbazole (6.36 g, 16.32 mmol), 9-(4-biphenyl)carbazole-3-boronic acid pinacol ester (8 g, 17.96 mmol), 100 mL toluene, potassium carbonate (4.51 g, 32.6 mmol), 20 mL water, and 20 mL ethanol were added to a 250 mL round-bottom flask. Under nitrogen protection, the mixture was stirred and heated to 50 °C. 0.3 g of catalyst Pd(PPh3)4 (tetra(triphenylphosphine)) was added, and the mixture was heated to reflux for 5 h before the reaction was stopped. After cooling, the mixture was separated into liquid and liquid phases. The organic phase was washed twice with 50 mL of water. The toluene was decolorized by passing it through a short silica gel column, and then the toluene was evaporated to about 40 mL. The liquid was heated to 90 °C until completely dissolved, and then 50 mL of isopropanol was added. The mixture was stirred and cooled to precipitate a solid, which was then filtered and dried to give 8 g of white solid compound B4, with a yield of 77%. B4 was further recrystallized twice using the same method, resulting in a purity of 99.1%. Finally, after purification by vacuum sublimation, the purity reached 99.81%.

[0101] The structural characterization results of compound B4 are as follows:

[0102] 1 H NMR (400MHz, CDCl3) δ8.47(d,J=1.6Hz,2H),8.25(d,J=7.6Hz,2H),7.79(dd,J=8.8and1.6Hz,2 H),7.67-7.61(m,8H),7.52(d,J=8.4Hz,2H),7.52-7.41(m,6H),7.33(dt,J=8.0and2.4Hz,2H).

[0103] 7. Synthesis of compound B5:

[0104]

[0105] 20.4 g (50 mmol) of 9'-phenyl-9H,9H'-3,3'-carbazole, 13.7 g (50 mmol) of 1-bromo-9,9-dimethyl-9H-fluorene, 200 mL of dichlorobenzene, and 13.8 g (100 mmol) of potassium carbonate were added to a 500 mL round-bottom flask. Under nitrogen protection, the mixture was stirred and heated to 50 °C. 0.47 g of catalyst CuI and 0.45 g of 1,10-o-phenanthroline were added, and the temperature was further increased to 150 °C. The reaction was then stopped after 8 h. The dichlorobenzene was heated and then decolorized using a short silica gel column. The dichlorobenzene was then distilled off under reduced pressure until approximately 100 mL remained. The solution was heated to 150 °C and completely dissolved. The mixture was stirred and cooled to precipitate a solid, which was then filtered and dried to give 15.9 g of a white solid, compound B5, with a yield of 53%. Compound B5 was further recrystallized twice using the same method, yielding a purity of 99.1%. Finally, after purification by sublimation, the purity was 99.79%.

[0106] The characterization results of compound B5 are as follows:

[0107] 1 H NMR (400MHz, CDCl3) δ8.55(dd,J=14.2,3.7Hz,1H),8.30–8.10(m,3H),7.97–7.78(m,4H),7.71(d,J=15. 0Hz, 1H), 7.67–7.43 (m, 10H), 7.37 (dd, J=28.3, 10.6Hz, 2H), 7.19 (dddd, J=28.7, 18.2, 14.3, 3.3Hz, 5H).

[0108] 8. Synthesis of compound B16:

[0109]

[0110] 24.2 g (50 mmol) of 9-[1,1'-biphenyl]-3-yl-3,3'-bi-9H-carbazole, 10.4 g (50 mmol) of 1-bromonaphthalene, 200 mL of dichlorobenzene, and 13.8 g (100 mmol) of potassium carbonate were added to a 500 mL round-bottom flask. Under nitrogen protection, the mixture was stirred and heated to 50 °C. 0.47 g of catalyst CuI and 0.45 g of 1,10-o-phenanthroline were added, and the temperature was further increased to 150 °C. The reaction was then stopped after 8 h. The dichlorobenzene was heated and then decolorized using a short silica gel column. The dichlorobenzene was then distilled off under reduced pressure until approximately 70 mL remained. The solution was heated to 150 °C and completely dissolved. The mixture was stirred and cooled to precipitate a solid, which was then filtered and dried to give 19.5 g of a white solid, compound B16, with a yield of 64%. Compound B16 was further recrystallized twice using the same method, yielding a purity of 99.5%. Finally, after purification by sublimation, the purity was 99.80%.

[0111] The characterization results of compound B16 are as follows:

[0112] 1 H NMR(400MHz, CDCl3)δ8.55(dd,J=14.2,3.7Hz,1H),8.30–8.12(m,4H),8.04(dd,J=14.8, 3.1Hz,1H),7.93–7.67(m,7H),7.67–7.55(m,4H),7.55–7.34(m,9H),7.29–7.02(m,4H).

[0113] 9. Synthesis of compound B20:

[0114]

[0115] 24.2 g (50 mmol) of 9-[1,1'-biphenyl]-3-yl-3,3'-bi-9H-carbazole, 12.9 g (50 mmol) of 9-bromophenanthrene, 200 mL of dichlorobenzene, and 13.8 g (100 mmol) of potassium carbonate were added to a 500 mL round-bottom flask. Under nitrogen protection, the mixture was stirred and heated to 50 °C. 0.47 g of catalyst CuI and 0.45 g of 1,10-o-phenanthroline were added, and the temperature was further increased to 150 °C. The reaction was then stopped after 8 h. The dichlorobenzene was heated and then decolorized using a short silica gel column. The dichlorobenzene was then distilled off under reduced pressure until approximately 80 mL remained. The solution was heated to 150 °C and completely dissolved. The mixture was stirred and cooled to precipitate a solid, which was then filtered and dried to give 21.5 g of a white solid, compound B20, with a yield of 65%. Compound B20 was further recrystallized twice using the same method, yielding a purity of 99.1%. Finally, after purification by sublimation, the purity was 99.85%.

[0116] The structural characterization results of compound B20 are as follows:

[0117] 1 H NMR(400MHz, CDCl3)δ8.98(dd,J=14.2,3.7Hz,1H),8.84(dd,J=14.2,3.7Hz,1H),8.63–8.41(m,2H),8.23(ddd,J=21.9,14 .0,9.5Hz,4H),8.11(dd,J=14.3,3.7Hz,1H),7.95–7.81(m,2H),7.81–7.55(m,10H),7.55–7.33(m,7H),7.29–7.00(m,4H).

[0118] 10. Synthesis of compound C1:

[0119]

[0120] 2-Chloro-3-phenylquinoxaline (9.6 g, 40 mmol), RM1 (19.9 g, 42 mmol), 120 mL toluene, potassium carbonate (11 g, 80 mmol), 40 mL water, and 40 mL ethanol were added to a 500 mL round-bottom flask. Under nitrogen protection, the mixture was stirred and heated to 50 °C. 0.18 g of catalyst Pd₂dba₃ and 0.19 g of Xphos were added, and the mixture was heated to reflux for 3 h before the reaction was stopped. After cooling, the mixture was separated into liquid and liquid phases. The organic phase was washed twice with 50 mL of water. Toluene was decolorized using a short silica gel column, and then the toluene was evaporated to approximately 50 mL. The solid was heated to 90 °C until completely dissolved, and then 200 mL of ethanol was added. The mixture was stirred and cooled to precipitate a solid, which was then filtered and dried to give 15 g of a white solid, compound C1, with a yield of 75%. Compound C1 was further recrystallized twice using the same method, yielding a purity of 99.2%. Finally, after purification by vacuum sublimation, the purity was 99.84%.

[0121] The structural characterization results of compound C1 are as follows:

[0122] 1HNMR(400MHz, CDCl3)δ8.95(t,J=1.6Hz,1H),8.84–8.77(m,1H),8.77–8.67(m,4H),8.25(ddd,J =10.3,6.2,3.4Hz,2H),7.89–7.78(m,3H),7.71–7.53(m,9H),7.37(tdd,J=6.7,4.5,2.4Hz,3H).

[0123] 11. Synthesis of compound C2:

[0124]

[0125] 2-Chloro-3-phenylquinoxaline (9.6 g, 40 mmol), RM2 (19.9 g, 42 mmol), 120 mL toluene, potassium carbonate (11 g, 80 mmol), 40 mL water, and 40 mL ethanol were added to a 500 mL round-bottom flask. Under nitrogen protection, the mixture was stirred and heated to 50 °C. 0.18 g of catalyst Pd2dba3 and 0.19 g of Xphos (2-dicyclohexylphosphine-2,4,6-triisopropylbiphenyl) were added, and the mixture was heated to reflux for 4 h before the reaction was stopped. After cooling, the mixture was separated into liquid and liquid phases. The organic phase was washed twice with 50 mL of water. Toluene was decolorized using a short silica gel column, and then the toluene was evaporated to approximately 50 mL. The dissolved toluene was heated to 90 °C, and 200 mL of ethanol was added. The mixture was stirred and cooled to precipitate a solid, which was then filtered and dried to give 18 g of a white solid, compound C2, with a yield of 90%. Compound C2 was further recrystallized twice using the same method, yielding a purity of 99.5%. Finally, after purification by vacuum sublimation, the purity was 99.77%.

[0126] The structural characterization results of compound C2 are as follows:

[0127] 1HNMR(400MHz, CDCl3)δ8.95(t,J=1.6Hz,1H),8.86–8.76(m,1H),8.76–8.66(m, 4H),8.32–8.18(m,2H),7.90–7.78(m,3H),7.67–7.53(m,9H),7.45–7.31(m,3H).

[0128] 12. Synthesis of compound C3:

[0129]

[0130] 2-(3-chlorophenyl)-3-phenylquinoxaline (22.2 g, 70 mmol), bis-pinacol borate (21.33 g, 84 mmol), 300 mL toluene, and 10.3 g potassium acetate were added to a 500 mL round-bottom flask. Under nitrogen protection, the mixture was stirred and heated to 50 °C. 0.4 g of catalyst Pd(dba)₂ and 0.34 g of 2-di-tert-butylphosphine-2',4',6'-triisopropylbiphenyl (XPhos) were added. The mixture was heated to reflux for 6 h, after which the reaction was stopped. The organic phase was decolorized by passing it through a short silica gel column while hot, and then toluene was rotary evaporated. After cooling, 10 mL of dichloromethane was added and heated to 40 °C until completely dissolved. Then, 50 mL of n-hexane was added, and the mixture was stirred and cooled to precipitate a solid. The solid was filtered and dried to give 22 g of a white solid, compound M1, with a yield of 78.5% and a purity of 98.8%.

[0131] The characterization results of intermediate M1 are as follows:

[0132] 1HNMR (400MHz, CDCl3) δ8.85–8.73(m,3H),8.27–8.17(m,1H),7.83–7.79(m,1H),7.71–7.54(m,6H),7.54–7.39(m,2H),1.58(s,12H).

[0133] M1 (11.15 g, 27.3 mmol), RM1 (10.1 g, 26 mmol), 80 mL toluene, sodium carbonate (5.5 g, 52 mmol), 25 mL water, and 25 mL ethanol were added to a 250 mL round-bottom flask. Under nitrogen protection, the mixture was stirred and heated to 50 °C. 0.3 g of catalyst Pd(PPh3)4 was added, and the mixture was further heated to reflux for 5 h before the reaction was stopped. After cooling, the mixture was separated into liquid and liquid phases. The organic phase was washed twice with 50 mL of water. Toluene was decolorized using a short silica gel column, and then rotary evaporated to remove approximately 40 mL. The toluene was heated to 90 °C until completely dissolved, and then 50 mL of ethanol was added. The mixture was stirred and cooled to precipitate a solid, which was then filtered and dried to give 12.6 g of a white solid, compound C3, with a yield of 84%. Compound C3 was further recrystallized twice using the same method, yielding a purity of 99.5%. Finally, after purification by vacuum sublimation, the purity was 99.98%.

[0134] The characterization results of compound C3 are as follows:

[0135] 1 HNMR(400MHz, CDCl3)δ8.92(d,J=0.9Hz,1H),8.87–8.77(m,4H),8.77–8.70(m,1H),8.29–8.18(m,2H), 7.93(t,J=1.6Hz,1H),7.86–7.75(m,3H),7.71–7.54(m,11H),7.50(t,J=7.7Hz,1H),7.46–7.34(m,3H).

[0136] 13. Synthesis of compound C4:

[0137]

[0138] M1 (11.15 g, 27.3 mmol), RM2 (10.1 g, 26 mmol), 80 mL toluene, sodium carbonate (5.5 g, 52 mmol), 25 mL water, and 25 mL ethanol were added to a 250 mL round-bottom flask. Under nitrogen protection, the mixture was stirred and heated to 50 °C. 0.3 g of catalyst Pd(PPh3)4 was added, and the mixture was further heated to reflux for 5 h before the reaction was stopped. After cooling, the mixture was separated into liquid and liquid phases. The organic phase was washed twice with 50 mL of water. Toluene was decolorized using a short silica gel column, and then rotary evaporated to remove approximately 40 mL. The toluene was heated to 90 °C until completely dissolved, and then 50 mL of ethanol was added. The mixture was stirred and cooled to precipitate a solid, which was filtered and dried to obtain 10.3 g of a white solid compound PQ-3Ph-4BPT, with a yield of 68.7%. Compound C4 was further recrystallized twice using the same method, yielding a purity of 99.5%. Finally, after purification by vacuum sublimation, the purity was 99.83%.

[0139] The characterization results of compound C4 are as follows:

[0140] 1 HNMR (400MHz, CDCl3) δ8.90–8.72(m,6H),8.32–8.16(m,2H),7.89–7.76(m,3H),7.76–7.55(m,12H),7.55–7.39(m,4H).

[0141] 14. Synthesis of compound C8:

[0142]

[0143] M1 (12.25 g, 30 mmol), 2-chloro-4-(2-naphthyl)-6-phenyl-1,3,5-triazine (9.22 g, 29 mmol), 90 mL toluene, potassium carbonate (8.3 g, 60 mmol), 30 mL water, and 20 mL ethanol were added to a 250 mL round-bottom flask. Under nitrogen protection, the mixture was stirred and heated to 50 °C. 0.3 g of catalyst Pd2dba3 and 0.28 g of Xphos (2-dicyclohexylphosphine-2,4,6-triisopropylbiphenyl) were added, and the mixture was heated to reflux for 6 h before the reaction was stopped. After cooling, the mixture was separated into liquid and liquid phases. The organic phase was washed twice with 50 mL of water. The toluene was decolorized by passing it through a short silica gel column, and then the toluene was evaporated to a final volume of about 60 mL. The volume of toluene was heated to 90 °C until completely dissolved, and then 30 mL of ethanol was added. The mixture was stirred and cooled to precipitate a solid, which was then filtered and dried to give 14.4 g of a white solid compound C8, with a yield of 85%. Compound C8 was further recrystallized twice using the same method, yielding a purity of 99.2%. Finally, after purification by vacuum sublimation, the purity reached 99.80%.

[0144] The characterization results of compound C8 are as follows:

[0145] 1 H NMR (400MHz, CDCl3) δ9.09 (t, J = 3.0 Hz, 1H), 8.64–8.42 (m, 4H), 8.42–8.28 (m, 2H), 8.21–7.95 (m, 5H), 7.88–7.43 (m, 11H), 7.32 (t, J = 15.0 Hz, 2H).

[0146] 15. Synthesis of compound C11:

[0147]

[0148] Add M1 (12.25 g, 30 mmol), 2-chloro-4-(9,9-dimethyl-9H-fluoren-2-yl)-6-phenyl-1,3,5-triazine (11.13 g, 29 mmol), 90 mL toluene, potassium carbonate (8.3 g, 60 mmol), 30 mL water, and 20 mL ethanol to a 250 mL round-bottom flask. Stir and heat to 50 °C under nitrogen protection, then add 0. After adding 3g of catalyst Pd₂dba₃ and 0.28g of Xphos (2-dicyclohexylphosphine-2,4,6-triisopropylbiphenyl), the reaction was continued at reflux for 6 hours, then stopped. After cooling, the mixture was separated into liquid and liquid phases. The organic phase was washed twice with 50mL of water, and toluene was decolorized by passing it through a short silica gel column. Toluene was then rotary evaporated until approximately 60mL remained. The solid was heated to 90℃ and completely dissolved, then 20mL of ethanol was added. The mixture was stirred and cooled to precipitate a solid, which was then filtered and dried to give 15.7g of a white solid, compound C11, with a yield of 83%. Compound C11 was further recrystallized twice using the same method, with a purity of 99.5%. Finally, after purification by vacuum sublimation, the purity was 99.92%.

[0149] The characterization results of compound C11 are as follows:

[0150] 1 H NMR (400MHz, CDCl3) δ8.75 (s, 1H), 8.49 (d, J = 10.0Hz, 2H), 8.36 (s, 2H), 8.27 (s, 1H), 8.06 (d,J=30.0Hz,3H),7.90(s,1H),7.86–7.42(m,11H),7.30(t,J=25.0Hz,4H),1.69(s,6H).

[0151] 16. Synthesis of compound C14:

[0152]

[0153] Add M1 (12.25 g, 30 mmol), 2-([1,1'-biphenyl]-4-yl)-4-chloro-6-(dibenzo[b,d]furan-3-yl)-1,3,5-triazine (12.58 g, 29 mmol), 90 mL toluene, potassium carbonate (8.3 g, 60 mmol), 30 mL water, and 20 mL ethanol to a 250 mL round-bottom flask, and stir and heat under nitrogen protection. At 50°C, 0.3 g of catalyst Pd₂dba₃ and 0.28 g of Xphos (2-dicyclohexylphosphine-2,4,6-triisopropylbiphenyl) were added. The mixture was then heated to reflux for 6 hours before the reaction was stopped. After cooling, the mixture was separated into liquid and liquid phases. The organic phase was washed twice with 50 mL of water. Toluene was decolorized by passing it through a short silica gel column, and then the toluene was evaporated by rotary evaporation until approximately 80 mL remained. The solid was heated to 90°C until completely dissolved, stirred, cooled, and precipitated. The solid was filtered and dried to give 13.8 g of white solid compound C14, with a yield of 68%. Compound C14 was further recrystallized twice using the same method, with a purity of 99.7%. Finally, it was purified by vacuum sublimation, with a purity of 99.96%.

[0154] The characterization results of compound C14 are as follows:

[0155] 1 H NMR (400MHz, CDCl3) δ8.76 (t, J = 3.0 Hz, 1H), 8.58-8.39 (m, 2H), 8.22 (d, J = 2.7Hz, 1H), 8.09-7.89 (m, 5H), 7.87-7.63 (m, 8H), 7.62-7.18 (m, 12H).

[0156] Example 2

[0157] In a preferred embodiment, refer to Figure 1 The structure shown is used to fabricate an organic electroluminescent device using a Sunicsp1710 evaporation deposition machine. The specific steps are as follows: First, a glass substrate (Corning glass 40mm×40mm×0.7mm) coated with 135nm ITO (indium tin oxide) is ultrasonically washed with isopropanol and pure water for 5 minutes each, followed by ultraviolet ozone cleaning. Then, the glass substrate is transferred to a vacuum deposition chamber as the anode layer 10. HT1 and HD are co-doped (HD doping mass ratio is 4%) and deposited on a transparent ITO electrode under vacuum (approximately 10...). -7A hole injection layer 20 is formed by thermal deposition of HT1 with a thickness of 20 nm. A 90 nm thick HT1 layer is then vacuum-deposited on top of the hole injection layer 20 to form a first hole transport layer 30. A 10 nm thick HT2 layer is then vacuum-deposited on top of the first hole transport layer 30 to form a second hole transport layer 40. A 30 nm thick light-emitting layer 50 is then vacuum-deposited on top of the second hole transport layer 40. The light-emitting layer 50 is composed of 3% by mass of phosphorescent green guest GD1, 48.5% by mass of compound A3, and 48.5% by mass of compound C1. Then, an electron transport layer 60 with a thickness of 30 nm is formed by vacuum deposition of ET1 doped with 50% LiQ (lithium 8-hydroxyquinoline). Finally, a 2 nm thick layer of ytterbium (Yb, as the electron injection layer 70) and a magnesium-silver alloy with a doping mass ratio of 10:1 are sequentially deposited to form a cathode layer 80. Finally, the component was transferred from the deposition chamber to the glove box and encapsulated with UV-curable epoxy resin and a glass cover containing a desiccant. During the above manufacturing steps, the deposition rates of the organic material, ytterbium, and Mg were maintained at 0.1 nm / s, 0.05 nm / s, and 0.2 nm / s, respectively. The component structure is represented as: ITO (135 nm) / HT1:4%HD (20 nm) / HT1 (90 nm) / HT2 (10 nm) / compound A3:compound C1:GD1 (48.5%:48.5%:3%) / ET1:LiQ (5:5, 30 nm) / Yb (2 nm) / Mg:Ag (10:1, 150 nm). The structures of HT1 (CAS#:1174006-39-3), HD (PubChem CID 124163074), HT2 (PubChem CID 121477644), GD1, and ET1 (PubChem CID 146557529) are as follows:

[0158]

[0159] The structure of this element is represented as: ITO (135nm) / HT1:4%HD (20nm) / HT1 (90nm) / HT2 (10nm) / compound A3:compound C1:GD1 (48.5%:48.5%:3%) / ET1:LiQ (5:5, 30nm) / Yb (2nm) / Mg:Ag (10:1, 150nm).

[0160] Example 3

[0161] The experiment was conducted in the same manner as in Example 2, except that compounds A3 and C2 were used as the main components (mass fraction 48.5%:48.5%).

[0162] The structure of this element is represented as: ITO (135nm) / HT1:4%HD (20nm) / HT1 (90nm) / HT2 (10nm) / compound A3:compound C2:GD1 (48.5%:48.5%:3%) / ET1:LiQ (5:5, 30nm) / Yb (2nm) / Mg:Ag (10:1, 150nm).

[0163] Example 4

[0164] The experiment was conducted in the same manner as in Example 2, except that compounds A3 and C3 were used as the main components (mass fraction 48.5%:48.5%).

[0165] The structure of this element is represented as: ITO (135nm) / HT1:4%HD (20nm) / HT1 (90nm) / HT2 (10nm) / compound A3:compound C3:GD1 (48.5%:48.5%:3%) / ET1:LiQ (5:5, 30nm) / Yb (2nm) / Mg:Ag (10:1, 150nm).

[0166] Example 5

[0167] The experiment was conducted in the same manner as in Example 2, except that compounds A3 and C4 were used as the main components (mass fraction 48.5%:48.5%).

[0168] The structure of this element is represented as: ITO (135nm) / HT1:4%HD (20nm) / HT1 (90nm) / HT2 (10nm) / compound A3:compound C4:GD1 (48.5%:48.5%:3%) / ET1:LiQ (5:5, 30nm) / Yb (2nm) / Mg:Ag (10:1, 150nm).

[0169] Example 6

[0170] The experiment was conducted in the same manner as in Example 2, except that compounds B4 and C1 were used as the main components (mass fraction 48.5%: 48.5%).

[0171] The structure of this element is represented as: ITO (135nm) / HT1:4%HD (20nm) / HT1 (90nm) / HT2 (10nm) / compound B4:compound C1:GD1 (48.5%:48.5%:3%) / ET1:LiQ (5:5, 30nm) / Yb (2nm) / Mg:Ag (10:1, 150nm).

[0172] Example 7

[0173] The experiment was conducted in the same manner as in Example 2, except that compounds B4 and C2 were used as the main components (mass fraction 48.5%:48.5%).

[0174] The structure of this element is represented as: ITO (135nm) / HT1:4%HD (20nm) / HT1 (90nm) / HT2 (10nm) / compound B4:compound C2:GD1 (48.5%:48.5%:3%) / ET1:LiQ (5:5, 30nm) / Yb (2nm) / Mg:Ag (10:1, 150nm).

[0175] Example 8

[0176] The experiment was conducted in the same manner as in Example 2, except that compounds B4 and C3 were used as the main components (mass fraction 48.5%:48.5%).

[0177] The structure of this element is represented as: ITO (135nm) / HT1:4%HD (20nm) / HT1 (90nm) / HT2 (10nm) / compound B4:compound C3:GD1 (48.5%:48.5%:3%) / ET1:LiQ (5:5, 30nm) / Yb (2nm) / Mg:Ag (10:1, 150nm).

[0178] Example 9

[0179] The experiment was conducted in the same manner as in Example 2, except that compounds B4 and C4 were used as the main components (mass fraction 48.5%:48.5%).

[0180] The structure of this element is represented as: ITO (135nm) / HT1:4%HD (20nm) / HT1 (90nm) / HT2 (10nm) / compound B4:compound C4:GD1 (48.5%:48.5%:3%) / ET1:LiQ (5:5, 30nm) / Yb (2nm) / Mg:Ag (10:1, 150nm).

[0181] Example 10

[0182] The experiment was conducted in the same manner as in Example 2, except that compounds A2 and C8 were used as the main components (mass fraction 48.5%:48.5%).

[0183] Example 11

[0184] The experiment was conducted in the same manner as in Example 2, except that compounds A7 and C8 were used as the main components (mass fraction 48.5%:48.5%).

[0185] Example 12

[0186] The experiment was conducted in the same manner as in Example 2, except that compounds A8 and C11 were used as the main components (mass fraction 48.5%:48.5%).

[0187] Example 13

[0188] The experiment was conducted in the same manner as in Example 2, except that compounds A12 and C11 were used as the main components (mass fraction 48.5%: 48.5%).

[0189] Example 14

[0190] The experiment was conducted in the same manner as in Example 2, except that compounds B5 and C11 were used as the main components (mass fraction 48.5%: 48.5%).

[0191] Example 15

[0192] The experiment was conducted in the same manner as in Example 2, except that compounds B16 and C14 were used as the main components (mass fraction 48.5%: 48.5%).

[0193] Example 16

[0194] The experiment was conducted in the same manner as in Example 2, except that compounds B20 and C14 were used as the main components (mass fraction 48.5%:48.5%).

[0195] Comparative Example 1

[0196] The experiment was conducted in the same manner as in Example 2, except that compound A3 was used as the single host.

[0197] The structure of this element is represented as: ITO (135nm) / HT1:4%HD (20nm) / HT1 (90nm) / HT2 (10nm) / compound A3:GD1 (97%:3%) / ET1:LiQ (5:5, 30nm) / Yb (2nm) / Mg:Ag (10:1, 150nm).

[0198] Comparative Example 2

[0199] The experiment was conducted in the same manner as in Example 2, except that compound B4 was used as the single host.

[0200] The structure of this element is represented as: ITO (135nm) / HT1:4%HD (20nm) / HT1 (90nm) / HT2 (10nm) / compound B4:GD1 (97%:3%) / ET1:LiQ (5:5, 30nm) / Yb (2nm) / Mg:Ag (10:1, 150nm).

[0201] Comparative Example 3

[0202] The experiment was conducted in the same manner as in Example 2, except that compound C1 was used as the single host.

[0203] The structure of this element is represented as: ITO (135nm) / HT1:4%HD (20nm) / HT1 (90nm) / HT2 (10nm) / compound C1:GD1 (97%:3%) / ET1:LiQ (5:5, 30nm) / Yb (2nm) / Mg:Ag (10:1, 150nm).

[0204] Comparative Example 4

[0205] The experiment was conducted in the same manner as in Example 2, except that compound C2 was used as the single host.

[0206] The structure of this element is represented as: ITO (135nm) / HT1:4%HD (20nm) / HT1 (90nm) / HT2 (10nm) / compound C2:GD1 (97%:3%) / ET1:LiQ (5:5, 30nm) / Yb (2nm) / Mg:Ag (10:1, 150nm).

[0207] Comparative Example 5

[0208] The experiment was conducted in the same manner as in Example 2, except that compound C3 was used as the single host.

[0209] The structure of this element is represented as: ITO (135nm) / HT1:4%HD (20nm) / HT1 (90nm) / HT2 (10nm) / compound C3:GD1 (97%:3%) / ET1:LiQ (5:5, 30nm) / Yb (2nm) / Mg:Ag (10:1, 150nm).

[0210] Comparative Example 6

[0211] The experiment was conducted in the same manner as in Example 2, except that compound C4 was used as the single host.

[0212] The structure of this element is represented as: ITO (135nm) / HT1:4%HD (20nm) / HT1 (90nm) / HT2 (10nm) / compound C4:GD1 (97%:3%) / ET1:LiQ (5:5, 30nm) / Yb (2nm) / Mg:Ag (10:1, 150nm).

[0213] Performance characterization:

[0214] (I) Characterization of thermodynamic properties

[0215] The glass transition temperature Tg was determined by differential scanning calorimetry (DSC, TA Instruments DSC25 differential scanning calorimeter) at a heating rate of 10℃ / min; the decomposition temperature Td was the temperature at which 5% weight loss occurred in a nitrogen atmosphere, and was determined by TA Instruments TGA55 thermogravimetric analyzer at a nitrogen flow rate of 20mL / min. Specific data are shown in Table 1 below.

[0216] Table 1

[0217] A2 156 458 A3 160 464 A7 151 446 A8 165 472 A12 154 455 B4 135 442 B5 124 428 B16 111 414 B20 146 462 C1 96 351 C2 96 351 C3 103 392 C4 110 396 C8 115 418 C11 136 435 C14 140 452

[0218] As shown in the table, the compounds used in this invention all have glass transition temperatures above 95℃, are not prone to crystallization, and exhibit good film-forming properties. Their thermal decomposition temperatures are above 350℃, making them difficult to decompose and demonstrating excellent thermal stability.

[0219] (II) The luminous efficiency and EQE (external quantum efficiency) of the device were tested using a Suzhou Freundae FS-100GA4 tester. All measurements were performed at room temperature and in atmospheric conditions. The device operates at 10 mA / cm². 2 The specific performance data of operating voltage (V), luminous efficiency (CE), external quantum efficiency (EQE), and color coordinates (CIEx, CIEy) at current density are shown in Table 2.

[0220] Table 2

[0221]

[0222] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects: neither a single electron donor material nor a single electron acceptor material is suitable as a green light host, resulting in very low device efficiency. However, by using any combination of the electron donor material and the electron acceptor material of the present invention to form an excitocomplex host, the device efficiency is significantly improved.

[0223] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A light-emitting layer, characterized in that, The light-emitting layer comprises a host material and a guest material, wherein the host material is an excimer complex; the excimer complex is composed of an electron donor compound and an electron acceptor compound, wherein the electron donor compound is a compound having formulas A1 to A16 or a compound having formulas B1 to B14, and the electron acceptor compound has a structure shown in general formula C; Equations A1 to A16 are as follows: ； Equations B1 to B14 are as follows: ； Wherein, L2 is selected from phenylene, biphenylene, or fluorene; Ar5 and Ar6 are each independently selected from phenyl, biphenyl, naphthyl, phenanthryl, fluorene, carbazolyl, or dibenzofuranyl. The object material is phosphorescent green dye: .

2. The light-emitting layer according to claim 1, characterized in that, The electron acceptor type compound of general formula C is a compound having formulas C1 to C39, wherein formulas C1 to C39 are: 。 3. An organic electroluminescent element, characterized in that, It includes an anode layer (10), a hole injection layer (20), a first hole transport layer (30), a second hole transport layer (40), a light-emitting layer (50), an electron transport layer (60), an electron injection layer (70), and a cathode layer (80) stacked in sequence; wherein the light-emitting layer (50) is the light-emitting layer as described in claim 1 or 2.

4. The organic electroluminescent element according to claim 3, characterized in that, By weight percentage, the content of the host material in the light-emitting layer (50) is 92-98 wt%, and the content of the guest material is 2-8 wt%.

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